牛和小鼠早期胚胎发育过程中细胞谱系发育调控的比较

Comparison of cell lineage development and regulation during early embryonic development in cattle and mice

高产奶牛繁殖效率低是世界性难题,其中早期胚胎死亡率高是主要原因之一。当前对牛早期胚胎发育的研究有限,而对于小鼠这种模式动物的早期胚胎发育研究已相当深入。因此,本文从胚胎形态、转录因子以及信号通路3方面对牛和小鼠早期胚胎发育过程进行比较,以加深对牛早期胚胎发育的认识。经比较发现,受精后,牛和小鼠早期胚胎在不同时期发生母源因子降解、合子基因组激活、细胞极性建立和不对称分裂,最终使得胚胎形态发生变化,形成具有3个胚层(滋养外胚层、上胚层和原始内胚层)的囊胚。此外,牛和小鼠早期胚胎发育过程中,多个转录因子及信号通路形成复杂网络调控细胞谱系分化。综上所述,在牛和小鼠早期胚胎发育过程中,相似的生物学事件陆续发生,但是细胞谱系分化的调控呈现差异性,提示我们将小鼠早期胚胎作为研究模型的局限性,该领域的研究对提高奶牛繁殖效率以及促进牛遗传改良工作具有重要意义。

Low reproductive efficiency of high-yielding dairy cows is a worldwide challenge,among which the high mortality rate of early embryos is one of the main reasons.Scientists have gained insightful knowledge into early embryonic development in mice while very little work has been performed in cattle.To better understand the early embryonic development in cattle,we compared early embryonic development in cattle and mice from the perspectives of embryo morphology,transcription factors and signaling pathways.It was found that after fertilization,degradation of maternal factors,zygotic genome activation,construction of cell polarity and asymmetric division occurred at different periods in the early embryos of cattle and mice.Eventually,embryos develop to blastocysts with three germ layers(trophectoderm,epiblast and primitive endoderm).Furthermore,multiple transcription factors and signaling pathways form complicated networks to regulate cell lineage differentiation during early embryonic development in cattle and mice.In summary,similar biological events occur one after another at the early embryonic development in cattle and mice,but the regulation of cell lineage differentiation is different,suggesting the limitations of using the early embryo of mouse as a research model.The study in this field plays a crucial role in improving reproductive efficiency of dairy cows and promoting the genetic improvement in cattle.